Cancer Immune Checkpoint Research Articles

Clinical development of immunotherapy for prostate cancer.

Prostate cancer is the most common cancer in men, and the second leading cause of cancer-related death in Western countries. Prostate cancer-related death occurs in patients with metastatic castration-resistant prostate cancer. Although several new drugs for castration-resistant prostate cancer have been approved, each of these has prolonged survival by just a few months. Consequently, new therapies are sorely needed. Recently, it has been recognized that immunotherapy is an effective treatment for prostate cancer patients. Several strategies, such as cancer vaccines and immune checkpoint inhibitors, have been investigated in clinical studies for prostate cancer patients. In the present review, the results of the most recent clinical studies investigating immunotherapy in prostate cancer patients are reported, and the future clinical development of immunotherapy for prostate cancer is discussed.

Combination therapy of cancer with cancer vaccine and immune checkpoint inhibitors: A mathematical model.

In this paper we consider a combination therapy of cancer. One drug is a vaccine which activates dendritic cells so that they induce more T cells to infiltrate the tumor. The other drug is a checkpoint inhibitor, which enables the T cells to remain active against the cancer cells. The two drugs are positively correlated in the sense that an increase in the amount of each drug results in a reduction in the tumor volume. We consider the question whether a treatment with combination of the two drugs at certain levels is preferable to a treatment by one of the drugs alone at ‘roughly’ twice the dosage level; if that is the case, then we say that there is a positive ‘synergy’ for this combination of dosages. To address this question, we develop a mathematical model using a system of partial differential equations. The variables include dendritic and cancer cells, CD4+ and CD8+ T cells, IL-12 and IL-2, GM-CSF produced by the vaccine, and a T cell checkpoint inhibitor associated with PD-1. We use the model to explore the efficacy of the two drugs, separately and in combination, and compare the simulations with data from mouse experiments. We next introduce the concept of synergy between the drugs and develop a synergy map which suggests in what proportion to administer the drugs in order to achieve the maximum reduction of tumor volume under the constraint of maximum tolerated dose.

An Anti-Programmed Death-1 Antibody (αPD-1) Fusion Protein That Self-Assembles into a Multivalent and Functional αPD-1 Nanoparticle.

Cancer immune checkpoint therapy has achieved remarkable clinical successes in various cancers. However, current immune checkpoint inhibitors block the checkpoint of not only the immune cells that are important to cancer therapy but also the immune cells that are irrelevant to the therapy. Such an indiscriminate blockade limits the efficacy and causes the autoimmune toxicity of the therapy. It might be beneficial to use a carrier to target immune checkpoint inhibitors to cancer-reactive immune cells. Here, we explore a method to load the inhibitors into carriers. We used the anti-programmed death-1 antibody (αPD-1) as a model immune checkpoint inhibitor. First, we generated a recombinant single-chain variable fragment (scFv) of αPD-1. Then, we designed and generated a fusion protein consisting of the scFv and an amphiphilic immune-tolerant elastin-like polypeptide (iTEP). Because of the amphiphilic iTEP, the fusion was able to self-assemble into a nanoparticle (NP). The NP was proved to block the PD-1 immune checkpoint in vitro and in vivo. Particularly, the NP exacerbated diabetes development in nonobese diabetic mice as effectively as natural, intact αPD-1. In summary, we successfully expressed αPD-1 as a recombinant protein and linked αPD-1 to a NP, which lays a foundation to develop a delivery system to target αPD-1 to a subpopulation of immune cells.

The CD47-SIRPα signaling axis as an innate immune checkpoint in cancer.

Immune checkpoint inhibitors, including those targeting CTLA-4/B7 and the PD-1/PD-L1 inhibitory pathways, are now available for clinical use in cancer patients, with other interesting checkpoint inhibitors being currently in development. Most of these have the purpose to promote adaptive T cell-mediated immunity against cancer. Here, we review another checkpoint acting to potentiate the activity of innate immune cells towards cancer. This innate immune checkpoint is composed of what has become known as the 'don't-eat me' signal CD47, which is a protein broadly expressed on normal cells and often overexpressed on cancer cells, and its counter-receptor, the myeloid inhibitory immunoreceptor SIRPα. Blocking CD47-SIRPα interactions has been shown to promote the destruction of cancer cells by phagocytes, including macrophages and neutrophils. Furthermore, there is growing evidence that targeting of the CD47-SIRPα axis may also promote antigen-presenting cell function and thereby stimulate adaptive T cell-mediated anti-cancer immunity. The development of CD47-SIRPα checkpoint inhibitors and the potential side effects that these may have are discussed. Collectively, this identifies the CD47-SIRPα axis as a promising innate immune checkpoint in cancer, and with data of the first clinical studies with CD47-SIRPα checkpoint inhibitors expected within the coming years, this is an exciting and rapidly developing field.

Proteogenomic analysis of NCC-S1M, a gastric cancer stem cell-like cell line that responds to anti-PD-1

To elucidate signaling pathways that regulate gastric cancer stem cell (CSC) phenotypes and immune checkpoint, we performed a proteogenomic analysis of NCC-S1M, which is a gastric cancer cell line with CSC-like characteristics and is the only syngeneic gastric tumor cell line transplant model created in the scientific community. We found that the NCC-S1M allograft was responsive to anti-PD-1 treatment, and overexpressed Cd274 encoding PD-L1. PD-L1 was transcriptionally activated by loss of the TGF-β signaling. Il1rl1 protein was overexpressed in NCC-S1M cells compared with NCC-S1 cells that are less tumorigenic and less chemoresistant. Il1rl1 knockdown in NCC-S1M cells reduced tumorigenic potential and in vivo chemoresistance. Our proteogenomic analysis demonstrates a role of Smad4 loss in the PD-L1 immune evasion, as well as Il1rl1's role in CSC-like properties of NCC-S1M.

Dynamic versus static biomarkers in cancer immune checkpoint blockade: unravelling complexity.

Recently, there has been a coordinated effort from academic institutions and the pharmaceutical industry to identify biomarkers that can predict responses to immune checkpoint blockade in cancer. Several biomarkers have been identified; however, none has reliably predicted response in a sufficiently rigorous manner for routine use. Here, we argue that the therapeutic response to immune checkpoint blockade is a critical state transition of a complex system. Such systems are highly sensitive to initial conditions, and critical transitions are notoriously difficult to predict far in advance. Nevertheless, warning signals can be detected closer to the tipping point. Advances in mathematics and network biology are starting to make it possible to identify such warning signals. We propose that these dynamic biomarkers could prove to be useful in distinguishing responding from non-responding patients, as well as facilitate the identification of new therapeutic targets for combination therapy.

Relationship of Metabolic Alterations and PD-L1 Expression in Cisplatin Resistant Lung Cancer.

Despite numerous reports on immune checkpoint inhibitor for the treatment of non-small cell lung cancer (NSCLC), the response rate remains low but durable. Thus cisplatin still plays a major role in the treatment of NSCLC. While there are many mechanisms involved in cisplatin resistance, alteration in metabolic phenotypes with elevated levels of reactive oxygen species (ROS) are found in several cisplatin resistant tumors. These resistant cells become more reliant on mitochondria oxidative metabolism instead of glucose. Consequently, high ROS and metabolic alteration contributed to epithelial-mesenchymal transition (EMT). Importantly, recent findings indicated that EMT has a crucial role in upregulating PD-L1 expression in cancer cells. Thus, it is very likely that cisplatin resistance will lead to high expression of PD-L1/PD-1 which makes them vulnerable to anti PD-1 or anti PD-L1 antibody treatment. An understanding of the interactions between cancer cells metabolic reprogramming and immune checkpoints is critical for combining metabolism targeted therapies with immunotherapies.

Advances in Immunotherapy for Glioblastoma Multiforme.

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults. Patients with GBM have poor outcomes, even with the current gold-standard first-line treatment: maximal safe resection combined with radiotherapy and temozolomide chemotherapy. Accumulating evidence suggests that advances in antigen-specific cancer vaccines and immune checkpoint blockade in other advanced tumors may provide an appealing promise for immunotherapy in glioma. The future of therapy for GBM will likely incorporate a combinatorial, personalized approach, including current conventional treatments, active immunotherapeutics, plus agents targeting immunosuppressive checkpoints.

New Immunotherapy Strategies in Breast Cancer.

Breast cancer is the most commonly diagnosed cancer among women. Therapeutic treatments for breast cancer generally include surgery, chemotherapy, radiotherapy, endocrinotherapy and molecular targeted therapy. With the development of molecular biology, immunology and pharmacogenomics, immunotherapy becomes a promising new field in breast cancer therapies. In this review, we discussed recent progress in breast cancer immunotherapy, including cancer vaccines, bispecific antibodies, and immune checkpoint inhibitors. Several additional immunotherapy modalities in early stages of development are also highlighted. It is believed that these new immunotherapeutic strategies will ultimately change the current status of breast cancer therapies.

Regulatory T cells in cancer immunotherapy.

FOXP3-expressing regulatory T (Treg) cells, which suppress aberrant immune response against self-antigens, also suppress anti-tumor immune response. Infiltration of a large number of Treg cells into tumor tissues is often associated with poor prognosis. There is accumulating evidence that the removal of Treg cells is able to evoke and enhance anti-tumor immune response. However, systemic depletion of Treg cells may concurrently elicit deleterious autoimmunity. One strategy for evoking effective tumor immunity without autoimmunity is to specifically target terminally differentiated effector Treg cells rather than all FOXP3+ T cells, because effector Treg cells are the predominant cell type in tumor tissues. Various cell surface molecules, including chemokine receptors such as CCR4, that are specifically expressed by effector Treg cells can be the candidates for depleting effector Treg cells by specific cell-depleting monoclonal antibodies. In addition, other immunological characteristics of effector Treg cells, such as their high expression of CTLA-4, active proliferation, and apoptosis-prone tendency, can be exploited to control specifically their functions. For example, anti-CTLA-4 antibody may kill effector Treg cells or attenuate their suppressive activity. It is hoped that combination of Treg-cell targeting (e.g., by reducing Treg cells or attenuating their suppressive activity in tumor tissues) with the activation of tumor-specific effector T cells (e.g., by cancer vaccine or immune checkpoint blockade) will make the current cancer immunotherapy more effective.

PD-1 and its ligands are important immune checkpoints in cancer.

Checkpoint programmed death-1 (PD-1)/programmed cell death ligands (PD-Ls) have been identified as negative immunoregulatory molecules that promote immune evasion of tumor cells. The interaction of PD-1 and PD-Ls inhibits the function of T cells and tumor-infiltrating lymphocytes (TIL) while increasing the function of immunosuppressive regulatory T cells (Tregs). This condition causes the tumor cells to evade immune response. Thus, the blockade of PD-1/PD-L1 enhances anti-tumor immunity by reducing the number and/or the suppressive activity of Tregs and by restoring the activity of effector T cells. Furthermore, some monoclonal antibodies blockading PD-1/PD-Ls axis have achieved good effect and received Food and Drug Administration approval. The role of PD-1/PD-Ls in tumors has been well studied, but little is known on the mechanism by which PD-1 blocks T-cell activation. In this study, we provide a brief overview on the discovery and regulatory mechanism of PD-1 and PD-L1 dysregulation in tumors, as well as the function and signaling pathway of PD-1 and its ligands; their roles in tumor evasion and clinical treatment were also studied.

Cancer immunotherapy: from the lab to clinical applications-Potential impact on cancer centres' organisation.

This report covers the Immunotherapy sessions of the 2016 Organisation of European Cancer Institutes (OECI) Oncology Days meeting, which was held on 15th–17th June 2016 in Brussels, Belgium. Immunotherapy is a potential cancer treatment that uses an individual’s immune system to fight the tumour. In recent years significant advances have been made in this field in the treatment of several advanced cancers. Cancer immunotherapies include monoclonal antibodies that are designed to attack a very specific part of the cancer cell and immune checkpoint inhibitors which are molecules that stimulate or block the inhibition of the immune system. Other cancer immunotherapies include vaccines and T cell infusions. This report will summarise some of the research that is going on in this field and will give us an update on where we are at present.

Immunotherapy of colorectal cancer: new perspectives after a long path.

Although significant therapeutic improvement has been achieved in the last 10 years, the survival of metastatic colorectal cancer patients remains in a range of 28 to 30 months. Presently, systemic treatment includes combination chemotherapy with oxaliplatin and/or irinotecan together with a backbone of 5-fluorouracil/levofolinate, alone or in combination with monoclonal antibodies to VEGFA (bevacizumab) or EGF receptor (cetuximab and panitumumab). The recent rise of immune checkpoint inhibitors in the therapeutic scenario has renewed scientific interest in the investigation of immunotherapy in metastatic colorectal cancer patients. According to our experience and view, here, we review the immunological strategies investigated for the treatment of this disease, including the use of tumor target-specific cancer vaccines, chemo-immunotherapy and immune checkpoint inhibitors.

Developing immunotherapies for childhood cancer

The development of immune-based treatment (immunotherapy) for childhood cancer is a rapidly advancing field with impressive results already achieved in children with leukaemia.1 ,2 For cancers resistant to conventional treatments,...

Lymphocyte-activation gene-3, an important immune checkpoint in cancer.

Immunotherapy has recently become widely used in lung cancer. Many oncologists are focused on cytotoxic T lymphocyte antigen‐4 (CTLA‐4), programmed cell death ligand‐1 (PD‐L1) and programmed cell death‐1 (PD‐1). Immunotherapy targeting the PD‐1/PD‐L1 checkpoints has shown promising efficacy in non‐small cell lung cancer (NSCLC), but questions remain to be answered. Among them is whether the simultaneous inhibition of other checkpoints could improve outcomes. Lymphocyte‐activation gene‐3 (LAG‐3) is another vital checkpoint that may have a synergistic interaction with PD‐1/PD‐L1. Here we review the LAG‐3 function in cancer, clinical trials with agents targeting LAG‐3 and the correlation of LAG‐3 with other checkpoints.

Abstract 2222: Dual inhibition of cancer stemness and immune checkpoint genes by targeting Stat3

Abstract Highly malignant stemness-high cancer cells, also termed cancer stem cells, have been found to hijack stemness genes important for embryonic stem cells to acquire a state of high-stemness. Cancer stemness has been associated with enhanced tumorigenicity and resistance to chemotherapies. Moreover, stemness-high cancer cells have been isolated from a variety of human cancer types. Therefore, targeting cancer stemness holds significant promise for advancing cancer treatment. Recent clinical success with antibodies targeting PD1 and PDL1 has validated that cancer cells can hijack immune checkpoint genes to subvert endogenous anticancer surveillance by the immune system. It is, therefore, highly desirable to develop therapeutics that simultaneously target both cancer cell stemness and immune checkpoints. The transcription factor Signal Transducer and Activator of Transcription 3 (Stat3) is activated by a multitude of upstream oncogenic pathways and cytokine receptors. Aberrant and constitutive activation of Stat3 has been found in a wide variety of human cancers, and has also been implicated in cancer cell proliferation, survival, and immune evasion. By using aiRNA (asymmetric RNA duplexes) we have achieved potent Stat3 silencing with precision in stemness-high cancer cells. We observed that Stat3 silencing leads to simultaneous down regulation of cancer cell stemness and immune checkpoint gene expression. Treatment of stemness-high cancer cells with BB608, a small molecule inhibitor of Stat3, led to simultaneous inhibition of stemness-high cancer cell survival and self-renewal, as well as downregulation of immune checkpoint genes, including IDO1 in vitro and in vivo. Furthermore, while expression of stemness genes and immune checkpoint genes in tumor tissues are known to predict poor patient survival, patients with higher expression levels of stemness genes and immune checkpoint genes showed prolonged overall survival after treatment with BB608 in clinical trials. Targeting Stat3 is, therefore, a promising strategy to achieve dual inhibition of cancer cell stemness and immune evasion. Citation Format: Yuan Gao, Sarah Keates, Eric Hsu, Janet Huang, Emily Brooks, Matt Hitron, Youzhi Li, Harry A. Rogoff, Chiang Li. Dual inhibition of cancer stemness and immune checkpoint genes by targeting Stat3. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2222.

A Perspective of Immunotherapy for Prostate Cancer.

In cancer patients, the immune system is often altered with an excess of inhibitory factors, such as immunosuppressive cytokines, produced by regulatory T cells (Treg) or myeloid-derived suppressor cells (MDSC). The manipulation of the immune system has emerged as one of new promising therapies for cancer treatment, and also represents an attractive strategy to control prostate cancer (PCa). Therapeutic cancer vaccines and immune checkpoint inhibitors have been the most investigated in clinical trials. Many trials are ongoing to define the effects of immune therapy with established treatments: androgen deprivation therapy (ADT) and chemotherapy (CT) or radiotherapy (RT). This article discusses some of these approaches in the context of future treatments for PCa.

Noncoding RNAs in Cancer Immunology.

Cancer immunology is the study of interaction between cancer cells and immune system by the application of immunology principle and theory. With the recent approval of several new drugs targeting immune checkpoints in cancer, cancer immunology has become a very attractive field of research and is thought to be the new hope to conquer cancer. This chapter introduces the aberrant expression and function of noncoding RNAs, mainly microRNAs and long noncoding RNAs, in tumor-infiltrating immune cells, and their significance in tumor immunity. It also illustrates how noncoding RNAs are shuttled between tumor cells and immune cells in tumor microenvironments via exosomes or other microvesicles to modulate tumor immunity.

Adoptive immunotherapy utilizing cancer antigen-specific T-cell receptors.

Synthetic immunology based on rapidly-advancing gene-engineering and immunobiology has made novel anticancer adoptive immunotherapies, using gene-modified T lymphocytes to express cancer antigen-specific receptors, a reality. Various technological innovations have overcome recent difficulties and achieved clear and long-lasting clinical efficacy against tumors, while seeking more powerful effector gene-modified T cells has yielded serious treatment-related adverse events. In this article, along with introducing our clinical trial for a novel anti-leukemia adoptive immunotherapy regimen using gene-modified autologous lymphocytes to express leukemia antigen Wilms Tumor 1(WT1)-specific T cell receptor (TCR) against refractory acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS), we provide an overview of the current status of this emerging treatment option and discuss its future form in the context of neoantigens encoded by mutated genes in cancer cells and immune checkpoint inhibitors.

Immune checkpoint blockade therapy for bladder cancer treatment.

Bladder cancer remains the most immunogenic and expensive malignant tumor in the United States today. As the 4th leading cause of death from cancer in United States, Immunotherapy blocking immune checkpoints have been recently been applied to many aggressive cancers and changed interventions of urological cancers including advanced bladder cancer. The applied inhibition of PD-1-PD-L1 interactions can restore antitumor T-cell activity and enhance the cellular immune attack on antigens. The overall goals of this short review article are to introduce current cancer immunotherapy and immune checkpoint inhibitors, and to provide new insight into the underlying mechanisms that block immune checkpoints in tumor microenvironment. Furthermore, this review will address the preclinical and clinical trials to determine whether bladder cancer patients could benefit from this new cancer therapy in near future.